Corporations are increasingly relying on the use of cellular technology by their employees, yet enterprises have traditionally lacked adequate means to control cellular service in terms of costs, Quality of Service, and corporate monitoring. This is because cellular service has conventionally been controlled by wireless carrier networks and managed independently of, and with no connectivity to, the enterprise voice and data networks.
Many contemporary mobile phones are available that support both cellular and other broadband radio technologies. For example, numerous mobile phones, or user equipments, are currently or will be commercially available that support a combination of the Global System for Mobile communications (GSM) and/or CDMA IS-95, as well as 3G technologies such as UMTS, HSPA or CDMA 1XRTT, 4G technologies such as LTE or WiMAX, and unlicensed technologies such as Wi-Fi. A wide range of Internet applications may then be accessed from user equipments featuring dual-mode, tri-mode or multi-mode technologies using wireless broadband, such as 3G UMTS, 4G WiMAX and unlicensed WiFi. For example, voice over IP (VoIP) traffic may be carried over alternative radio interfaces, such as 3G UMTS, 4G WiMAX and unlicensed WiFi.
The 3GPP has defined the Voice Call Continuity (VCC) specifications in order to describe how a voice call may be maintained as a mobile phone moves between circuit switched and packet switched radio domains. As referred to herein, a 2G service comprise a circuit switched service, and a 3G, 4G or unlicensed service comprises a packet switched service.
When a user equipment (UE) becomes attached and detached from wireless access points, such as WiFi hotspots, a client application in a contemporary UE communicates the radio conditions to a VCC platform in the network. This allows circuit switched and IP call legs to be originated and terminated such that the speech path is transferred between domains transparently to the end user.
Because most packet-switched access points utilize fixed backhaul technologies, seamlessly moving between packet and circuit domains allows the best quality and most cost efficient radio to be used at any given point in time, regardless of the transport technology used for the media. Service providers are interested in VCC in order to offer products directed to particular market segments, e.g., enterprise users. Enterprises are also interested in VCC typically for enabling dual-mode devices, e.g. GSM and WiFi, to be able to circumvent the service providers network.